Dual-winding synchronous reluctance machine composed of an excitation winding and a separate power winding

Abstract

A rotating field machine (200) including a stator (140) and a rotor (150) are provided. In particular, a dual-winding rotating field machine (200) in which the stator (140) includes two separate windings can be provided. In one example implementation, the stator (140) can include an excitation winding (220) configured to control an excitation current and a power winding (230) configured to control power flow to an electrical system. The dual-winding rotating field machine (200) can further include a starting mode and a generating mode. During the starting mode, both the excitation winding (220) and the power winding (230) can be coupled to one or more switching power converters (170). During the generating mode, the power winding (230) can be coupled to a variable frequency bus and the power converter (170) can be used to manage excitation power only.

What is claimed is: 
     
       1. A rotating field machine, the rotating field machine comprising:
 a stator; 
 a rotor, the rotor being mounted for rotation with respect to the stator; 
 wherein the stator comprises:
 a first winding, the first winding being an excitation winding configured to receive an excitation current; and 
 a second winding physically decoupled from the first winding, wherein the second winding is a power winding configured to accommodate power flow through the rotating field machine; 
 
 wherein the excitation winding and the power winding are located in the stator such that the excitation winding and power winding are in electrical quadrature with respect to one another; 
 wherein the excitation winding is associated with a d-axis current and the power winding is associated with a q-axis current for the rotating field machine, the first winding 90° out of electrical phase with respect to the second winding; 
 the rotating field machine further comprising a power converter and a control device, the control device being configured to operate the rotating field machine in either a starting mode or a generating mode, wherein the control device is configured so that, during the starting mode, both the excitation winding and the power winding are coupled to the power converter, and is further configured so that, in the generating mode, the power winding is decoupled from the power converter. 
 
     
     
       2. The rotating field machine of  claim 1 , wherein the power winding is coupled to a DC bus via a bridge rectifier. 
     
     
       3. The rotating field machine of  claim 1 , wherein during a generating mode, the power winding is coupled to a variable frequency constant voltage bus. 
     
     
       4. The rotating field machine of  claim 2 , wherein a control device is configured to control the power converter to manage excitation current flowing in the excitation winding to control a generated power in the power winding. 
     
     
       5. A control system for operating a rotating field machine, the rotating field machine comprising a stator and a rotor, the rotor being mounted for rotation with respect to the stator, the stator comprising an excitation winding configured to receive an excitation current and a power winding physically decoupled from the excitation winding and configured to accommodate power flow in the rotating field machine, the control system configured to perform operations, the operations comprising:
 determining to operate the rotating field machine in a starting mode; 
 wherein during the starting mode, the operations comprise: 
 energizing the excitation winding and the power winding with one or more power converters; and 
 operating the one or more power converters to start the rotating field machine; 
 determining to operate the rotating field machine in a generating mode; 
 wherein during the generating mode, the operations comprise:
 decoupling the power winding from the one or more power converters; and 
 operating the one or more power converters to manage excitation current flowing in the excitation winding to control a generated power in the power winding; 
 
 wherein the excitation winding and the power winding are located in the stator such that the excitation winding and power winding are in electrical quadrature with respect to one another; 
 wherein the excitation winding is associated with a d-axis current and the power winding is associated with a q-axis current for the rotating field machine, and wherein the excitation winding is 90° out of electrical phase with respect to the power winding. 
 
     
     
       6. The control system of  claim 5 , wherein during the generating mode, the operations comprise coupling the power winding to a DC bus via a rectifier. 
     
     
       7. The control system of  claim 5 , wherein during the generating mode, the operations comprise coupling the power winding to an AC bus. 
     
     
       8. A method of operating a rotating field machine, the rotating field machine comprising a stator and a rotor, the rotor being mounted for rotation with respect to the stator, the stator comprising an excitation winding configured to receive an excitation current and a power winding physically decoupled from the excitation winding and configured to accommodate power flow in the rotating field machine, the method comprising:
 determining to operate the rotating field machine in a starting mode;
 wherein during the starting mode, the method comprises:
 energizing the excitation winding and the power winding with a power converter; and 
 operating the power converter to start the rotating field machine; 
 determining to operate the rotating field machine in a generating mode;
 wherein during the generating mode, the method comprises: 
 decoupling the power winding from the power converter; and 
 operating the power converter to manage excitation current flowing in the excitation winding to control a generated power in the power winding; 
 
 
 
 wherein the excitation winding and the power winding are located in the stator such that the excitation winding and power winding are in electrical quadrature with respect to one another; and 
 wherein the excitation winding is associated with a d-axis current and the power winding is associated with a q-axis current for the rotating field machine, and wherein the excitation winding is 90° out of electrical phase with respect to the power winding. 
 
     
     
       9. The method of  claim 8 , wherein the excitation winding and the power winding are located in the stator such that the excitation winding and power winding are in electrical quadrature with respect to one another. 
     
     
       10. The method of  claim 8 , wherein during the generating mode, the method comprises coupling the power winding to a DC bus via a rectifier. 
     
     
       11. The method of  claim 8 , wherein during the generating mode, the method comprises coupling the power winding to an AC bus.